Cube Audio
Single full-range driver, no crossover — the most direct path from amplifier to ear.
Grzegorz Rulka · Poland · Boutique
- Design: No-crossover full-range drivers for phase-perfect, coherent midrange presentation.
- Tendency: Tonally rich, midrange-saturated, holographic — particularly natural on vocals and acoustic music.
- Trade-off: Reduced bass extension and treble energy vs. multi-way designs; demanding room setup.
Philosophy
Cube Audio designs single full-range driver speakers for use without crossovers. The philosophy follows the SET amplifier ideal: minimal signal path, maximum coherence. Drivers are designed in-house with a focus on pistonic linearity and low distortion at real-world listening levels.
The mainstream loudspeaker accepts the crossover as a necessary cost: split the signal across drivers optimised for their bands, and pay for the integration with phase complexity and a network of components between amplifier and cone. Cube Audio argues the cost is not necessary if a single driver can cover the range honestly. The in-house drivers — built around a paper cone with multiple whizzer sections and neodymium motors — are engineered to stay pistonic across the band without breaking into the ragged top-octave behaviour that sank earlier full-range designs. The result is a speaker the amplifier sees as one continuous load with no crossover between it and the cone, which is why the brand is voiced for and sold to single-ended-triode listeners. The trade is deliberate and named: the bottom octave and the very top are given up in exchange for a midrange coherence and a phase integrity that multi-way designs cannot reach because they are not trying to.
Leadership & Origin
Grzegorz Rulka builds Cube Audio in Poland, designing the full-range drivers in-house rather than sourcing them — the driver is the company's core intellectual property, not the cabinet. The brand emerged from the contemporary single-driver revival, which set out to answer the historical objection to full-range designs (limited bandwidth, cone break-up) with modern materials and motor engineering rather than with apology. Cube's position is that the single-driver, no-crossover speaker is not a vintage curiosity but a current design answer for the low-power-amplification listener, and the company has built its identity around the driver as the thing it makes, with the speaker as the thing the driver goes in.
Sonic Character
Cube Audio speakers are described as extraordinarily coherent, midrange-rich, and tonally saturated. The full-range driver eliminates crossover colorations — voices and acoustic instruments are presented with unusual directness. High sensitivity (typically 95–98 dB) enables single-ended triode pairing.
Strengths
- No crossover between amplifier and cone — the single full-range driver removes the phase complexity and component network that a multi-way design places in the signal path, which listeners hear as directness and coherence rather than as a measured spec
- In-house driver design — the multi-whizzer paper-cone driver is the company's own engineering, not an off-the-shelf part, so the brand owns the trade-offs it is making rather than inheriting them
- High sensitivity (typically 95–98 dB) by design — the speaker is built to be driven by a few watts of single-ended triode, making it one of the natural speaker partners for the SET amplifier
- Midrange saturation and holographic presentation on voice and acoustic instruments — the band where the single driver is most honest is the band most music lives in
Trade-offs
- Bottom-octave bass extension is given up — a single driver in a modest cabinet cannot move the air a dedicated woofer can, and bass-anchored listeners will hear the limit
- Top-octave air and sparkle are softer than a dedicated tweeter delivers — the full-range driver trades the last octave of treble energy for coherence through the midband
- Room placement is demanding — the design rewards near-field or treated rooms and careful positioning, and punishes casual placement more than a forgiving multi-way
- The intended result requires low-output-impedance, low-power amplification — in a high-feedback solid-state system the speaker works but the design intent is not served
Pairing Guidance
Cube Audio speakers are designed specifically for low-power tube amplification — particularly SET designs using 300B, 2A3, or similar output tubes. They require careful room placement (near-field or treated rooms work best) and amplifiers with low output impedance to control the wide-range driver. In solid-state systems they function but the design intent is not served. The brand sits within the Musical Communication School as the no-crossover single-driver expression of the chain-as-system commitment — a different speaker tradition than DeVore Orangutan or Audio Note AN-E, with the same architectural posture.
Cube Audio is voiced for single-ended-triode and low-power tube amplification (300B, 2A3, 845, and similar), where the high sensitivity turns a few watts into full dynamic range. It sits in the Musical Communication School as the no-crossover single-driver expression of the chain-as-system commitment — a different speaker tradition than DeVore Orangutan (wide-baffle) or Audio Note AN-E (BBC-derived), reaching the same architectural posture by a different route. The canonical chain places it after a tube line stage and a Class A or SET amplifier, fed by a tonally dense source (NOS / R2R DAC or an analog front end). Anti-pairings: high-power solid-state where the design intent is lost, large rooms requiring deep bass at high SPL, and listeners who anchor on bottom-octave slam or top-octave sparkle.
Design Families
The brand's flagship-tier statement of the single-driver argument — a larger cabinet built around the full-range driver, voiced for SET amplification and the most complete expression of the no-crossover idea in the range.
More accessible cabinets carrying the same in-house full-range driver philosophy at smaller scale, plus the bare drivers themselves — the company sells the driver as well as the speaker, underscoring that the driver is the product.
Links
The Ideas Behind Cube Audio
Representative models — 1 product
Polish full-range widebander in a compact open-back cabinet — 96dB efficiency requires only 2–5W for full dynamic range.